Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif

doi:10.1063/1.4869758

Cited by 26 publications

(17 citation statements)

References 20 publications

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“…When the CNTs were biased as the negative electrode, electron emission occurred from the CNT nanotips, followed by impact ionization and recombination, which would further aid in decreasing the working voltage of the device. When the CNTs were biased negatively, the breakdown voltage in the air reduced to 242 V, while, for nitrogen, the breakdown was observed at 328 V, in agreement with [26] and [27]. The one-dimensional structure of CNTs aided in amplifying the electric field and induce discharge at a lower voltage as compared to traditional metallic ionization sensors.…”

Section: Resultsmentioning

confidence: 56%

Ionization Gas Sensor Using Suspended Carbon Nanotube Beams

Arunachalam

Izquierdo

Nabki

2020

Sensors

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An ionization sensor based on suspended carbon nanotubes (CNTs) was presented. A suspended CNT beam was fabricated by a low-temperature surface micromachining process using SU8 photoresist as the sacrificial layer. Application of a bias to the CNT beam generated very high non-linear electric fields near the tips of individual CNTs sufficient to ionize target gas molecules and initiate a breakdown current. The sensing mechanism of the CNT ionization sensor was discussed. The sensor response was tested in air, nitrogen, argon, and helium ambients. Each gas demonstrated a unique breakdown signature. Further, the sensor was tested with gaseous mixtures. The sensor exhibited good long-term stability and had comparable performance to other reported CNT-based ionization sensors in literature, which use high-temperature vapor deposition methods to grow CNTs. The sensor notably allowed for lower ionization voltages due to its reduced ionization gap size.

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Section: Resultsmentioning

confidence: 56%

Ionization Gas Sensor Using Suspended Carbon Nanotube Beams

Arunachalam

Izquierdo

Nabki

2020

Sensors

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“…In other words, the threshold for ionization as well as the TPs could be reduced by reducing the needle tip diameter. For instance, CNTs and metallic nanowires have been used to reduce the breakdown voltage down to dozens of volts [20–22]. Thus, the structure is very simple and flexible and there is no rigorous demand for the sensor.…”

Section: Resultsmentioning

confidence: 99%

“…The prebreakdown current or voltage was usually measured as the sensing signal, but the current was very small and on the order of pA, which was not very easy to measure. Much effort has been done to extensively lower the external voltage for the sensor making it suitable for low voltage electronics integration [20–22]. Our goal is to develop a simple low-cost breath sensor with good performance for in-home use.…”

Section: Introductionmentioning

confidence: 99%

Respiratory Monitoring by a Field Ionization Sensor Based on Trichel Pulses

Deng

Song

2014

Sensors

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In this paper, a novel method for respiratory monitoring is presented. The method is based on Trichel pulses (TPs) using a simple field ionization sensor which consists of a needle electrode and a plate electrode. Experiments have been conducted to demonstrate that different respiratory patterns, including normal, ultra-fast, deep breaths, and apnea could be easily monitored in real time by detecting the changes in the TP frequency. The vital capacity could also be assessed by calculating the variation of TP frequency. It is found that the operation principle of the proposed sensor is based on the effects of breath airflow and the atomized water in exhaled air on the TP frequency by changing the ionization process and the dynamics of charged particles in the short gap. The influences of applied voltage and ambient parameters have also been investigated.

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“…There are two useful ways for diminishing the required ionization voltage which are applying nanostructures on electrodes to make the benefit of field emission enhancement phenomenon and reducing the gap distance between electrodes [2]. According to the sharp tips of nanostructures, they have a higher local electric field which can improve the tunneling process between electrodes and reduce the ionization voltage [19]. Vertically aligned growth of nanostructures on the surface of electrodes decreases ionization voltage by improving the tunneling process as well as reducing the gap distance.…”

Section: Introductionmentioning

confidence: 99%

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

Ramezannezhad

Nikfarjam

Sichani

et al. 2022

Micro & Nano Letters

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The present study demonstrates a novel miniature planar device by the selective growth of ZnO nanowires for microplasma optical emission gas spectroscopy. Gold electrodes are fabricated on the silicon substrate by thermal evaporation and photolithography process with a 15 μm gap size. Zinc oxide (ZnO) nanowires, are selectively grown on the electrodes without using a seeding layer by a hydrothermal method which is a cost‐effective approach. Growth of vertically aligned ZnO nanowires on electrodes with sharp tips reinforce the field emission enhancement factor which results in lower microplasma generation voltage. The SEM characterizations reveals that ZnO nanowires are grown on electrodes, selectively. The diameter range and length of nanowires vary between 50 and 250 nm and 3 and 5 μm, respectively. Also, the gap distance between electrodes decreases from 15 μm to about 4–10 μm due to the growth of vertically aligned nanowires. The experimental tests are implemented for helium, nitrogen, and carbon dioxide gases at room temperature and atmospheric pressure. The results successfully exhibit the characteristic peaks and repeatable responses for all the samples. In addition, the required working voltage for microplasma formation of He, N2, and CO2 reduce 32%, 22%, and 20%, respectively, after ZnO nanowires growth. Besides, the electrodes sputtering rate significantly decreases during the tests due to the thermal stability of ZnO nanowires. According to the device performance, the proposed structure could be a promising candidate for relative low voltage, highly selective and stable optical emission spectroscopy for gas detection applications.

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Breakdown voltage reduction by field emission in multi-walled carbon nanotubes based ionization gas sensor

Cited by 26 publications

References 20 publications

Ionization Gas Sensor Using Suspended Carbon Nanotube Beams

Ionization Gas Sensor Using Suspended Carbon Nanotube Beams

Respiratory Monitoring by a Field Ionization Sensor Based on Trichel Pulses

Planar microplasma optical emission gas spectroscopy based on selective growth of ZnO nanowires

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